prepared commercially by a Diels-Alder reaction of between 1,3-butadiene and sulfur dioxide, followed by Raney nickel hydrogenation. The principal impurities are water, 3-sulfolene, 2-sulfolene and 2-isopropyl sulfolanyl ether. It is dried by passage through a column of molecular sieves. Distil it under reduced pressure through a column packed with stainless steel helices. Again dry it with molecular sieves and distil. [Cram et al. J Am Chem Soc 83 3678 1961, Coetzee Pure Appl Chem 49 211 1977.] Alternatively, it is stirred at 50o, and small portions of solid KMnO4 are added until the colour persists during 1hour. Dropwise addition of MeOH then destroys the excess KMnO4; the solution is filtered, freed from potassium ions by passage through an ion-exchange column and dried under vacuum. It has also been distilled in a vacuum from KOH pellets. It is hygroscopic. [See Sacco et al. J Phys Chem 80 749 1976, J Chem Soc, Faraday Trans 1 73 1936 1977, 74 2070 1978, Trans Faraday Soc 62 2738 1966.] Coetzee has reviewed the methods of purification of sulfolane, and also the removal of impurities. [Coetzee in Recommended Methods of Purification of Solvents and Tests for Impurities, Coetzee Ed. Pergamon Press, 1982, Beilstein 17 I 5, 17 III/IV 37, 17/1 V 39.]
Colorless oily liquid with a weak oily odor. Solidifies (freezing point is 79°) and sinks on first contact with water, then mixes with water. F.
Mixing Sulfolane in equal molar portions with any of the following substances in a closed container caused the temperature and pressure to increase: chlorosulfonic acid and oleum [NFPA 1991]. With nitrating agents (nitronium tetrafluoroborate in Sulfolane) very highly exothermic reactions are known to occur, [J. Org. Chem., 1978, 43, 4677].
Air & Water Reactions
Selective solvent for liquid-vapor extractions.
Special Hazards of Combustion Products: Toxic, irritating gases may be generated in fires.
Very mildly irritating to the eyes.